SENSITIVE AND RAPID DETECTION OF ENTEROBACTER SAKAZAKII IN INFANT FORMULA BY LOOP‐MEDIATED ISOTHERMAL AMPLIFICATION METHOD

Abstract

ABSTRACTEnterobacter sakazakii is an emergent pathogen associated with ingestion of infant formula milk and was defined in category “A” of the hazard identification by FAO and WHO on microorganisms, which is based on the strength of evidence of a causal association between their presence in powdered infant formula and illness in infants. In this study, a loop‐mediated isothermal amplification (LAMP) method has been developed for the detection of E. sakazakii in infant formula. The assay detected the species‐specific DNA sequence of the 16S‐23S rRNA internal transcribed spacer. The sensitivity of the detection is 1.2 cfu per 100 g infant formula with the selective enrichment. As the amplification is made under isothermal conditions, only a water bath or heating block is needed to maintain the required temperature. Thus, the method will be easily generalized and popularized in the future.PRACTICAL APPLICATIONS Enterobacter sakazakii is an emerging opportunistic pathogen associated with meningitis, bacteria and necrotizing enterocolitis in neonates. Powdered infant formulae have been implicated as the source of infection in neonatal meningitis. Thus, in order to minimize the hazard caused by E. sakazakii, it is of utmost importance to develop a rapid, sensitive and simple method for the early detection of this bacterium in infant formula.In our study, the E. sakazakii was detected sensitively and rapidly in the infant formula by the loop‐mediated isothermal amplification (LAMP) assay. LAMP is easy to perform once the appropriate primers are prepared. The LAMP method will be a simple and rapid method for the scene detection of E. sakazakii as only four primers, a Bst polymerase and a regular laboratory bath are needed.